It's me.
Handle it the same way you would handle any other dating esque situation with a lady. Find a way to find out if she's single, first off, and then move slowly from there towards a date.
I wouldn't treat it any differently than that, even if your final goal is essentially a tickle-buddy, because too much too fast tends to not work so well.
But then, I don't know the situation at all, nor do I know you or her. Just do what you think is appropriate and don't be a dick. You know the situation better than us, so just use your own judgment and good luck.
Oh, I say don't treat it differently, mostly because it really isn't all that different. Even if I post here, if someone walks up to me and says hey I think you have this fetish, would you mind if I tickle you, yeah, I'm still going to be creeped out. But yeah.
Etc